Azadore m



(ModeL) A. M. DOANB. EXHAUST FAN.

No. 435.602.. Patented Sept. 2. 1890.

I UNITED STATES PATENT OFFICE.

AZADORE M. DOANE, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TO EDIVIN P. HIGGINS, OF SAME PLACE.

EXHAUST-FAN.

SPECIFICATION forming part of Letters Patent No. 435,602, dated September 2, 1890.

Application filed July 30, 1889. Serial No. 319,175 (ModeL) To all whom it may concern:

Be it known that I, AZADORE M. DOANE, of Chicago, in the county of (look and State of Illinois, have invented certain new and useful Improvements in Exhaust-Fans; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to a novel construction in exhaust fans for inducing currents of air of that kind having obliquely-arranged blades or wings; and it consists in the features of construction and combination of parts hereinafter fully described, and pointed out in the appended claims.

In the drawings, Figure l is a view in front elevation of a fan constructed in accordance with my invention. Fig. 2 is a side elevation of the same.

This apparatus is designed more particularly to be employed for forcing a current of air through a suitable pipe-for example, the pipes used in house-ventilating, in which case the said fan would be located transversely within and fill the ventilating-pipe.

In said drawings, A indicates a hub, which may be of any familiar construction, and which is mounted upon a suitable shaft A, by which it is driven. Said hub is herein shown as formed by two disks a a, each of which is provided with a shaft-aperture a.

B B B indicate a plurality of radial blades or wings, said blades or wings being attached at their bases or inner ends to the hub A, and in the present instance secured to each of the disks a a comprising said hub. Each of said blades B is constructed wider at the base 1) than at the outer end I), and the blades are spirally bent or twisted and arranged with a greater pitch at their inner than at their outer ends. Said blades, furthermore, are bodily inclined to the axis of the shaft, so that they stand obliquely to the latter, the inclination of the blades being outward and forward or in thedirection in which the air-current moves. The said widened inner ends of the blades, therefore, are secured to the hub at a considerable angle to the axial line thereof, conveniently about forty-five degrees of are, and said blades are gradually bent or deflected in theirbody port-ion, so that their outer narrowed ends will stand more nearly at right angles to such axial line, while the outer ends of the blades extend forward of or overhang the hub.

The blades may in practice be made either of cast or wrought metal or any otherconvenient material. In the particular construction illustrated they are made of sheet metal and provided with strengthening-ribs b 19 along their rear edges; but such ribs are not necessary, provided the blades are otherwise stifiened or made sufficiently strong. It is obvious that the bodily incline of the blades, and also the angles at which their ends are located relative to the hub and to each other, can be changed or modified, as will be found most convenient, although the construction illustrated is found effective in practice.

It has heretofore been usual to so construct the blades-of exhaust-fans that their outer ends, which revolve with greatest velocity, have the greatest width, and consequently do the greater part of the work.

An obvious advantage gained by the construct-ion herein set forth is the equalization of the quantity of air set in motion at the inner and outer parts of the fan, due to the fact that the outer ends of the blades, which revolve with a greater velocity than the inner ends, are narrower than said inner ends and have a less pitch. Another advantage gained by this construction is the direction given to the air set in motion thereby.

Heret-ofore the exhaust-fans commonly used have been so constructed that the current of air induced thereby is thrown outwardly against the sides of the pipes in which said fan is located-that is to say, spreads out or diverges-thus causing a considerable friction between it and the walls of the pipes, thereby retarding the force of the current. The same is true when the fan is working without any surrounding pipe, the air moved by the fan being thrown outward, so as to impinge against the surrounding air instead of moving in a solid column through it.

The construct-ion herein described is provided for the purpose of directing the current of air either in parallel lines or inwardly toward the center of the pipe, and thereby attaining a strong and concentrated current of air with the same amount of power, this result being produced by the bodily inclination of the blades hereinbefore described.

I claim as my invention--- 1. An exhaust-fan comprising a supportingshaft and a plurality of radial blades or wings which are bodily inclined in a direction from their point of attachment to the shaft forwardly or toward the delivery side of the fan, the said blades being separate or disconnected from each other at their side edges, whereby the air moved by the blades passes laterally between the blades and is concentrated or di rected obliquely inward toward the axis of the fan, substantially as described.

2. An exhaust-fan comprisinga supportingshaft and a plurality of radial blades or Wings which have a greater pitch at their inner than at their outer ends and are bodily inclined with reference to the shaft-axis in a direction from their point of attachment to the shaft forwardly or toward the delivery side of the fan, substantially as described.

3. An exhaust-fan comprising a supportingshaft and a plurality of radial blades or wings having a greater width at their inner than at their outer ends, said blades or wings being bodily inclined with reference to the shaftaxis in a direction from their point of attachment to the shaft forwardly, or toward the delivery side of the fan, substantially as described.

4. An exhaust-fan comprising a supportingshaft and a plurality of radial blades or wings having a greater width and pitch at their inner than at their outer ends, said blades or wings being bodily inclined with reference to the shaft-axis in a direction from their point of attachment to the shaft forwardly, or toward the delivery side of the fan, substan tially as described.

In testimony that I claim the foregoing as my invention I aflix my signature in presence of two witnesses.

AZADORE M. DOANE.

Witnesses: l

O. CLARENCE POOLE, HARRY COBB KENNEDY. 

